A general approach toward shape-controlled synthesis of silicon nanowires.

Controlling the morphology, electronic properties, and growth direction of nanowires (NWs) is an important aspect regarding their integration into devices on technologically relevant scales. Using the vapor-solid-solid (VSS) approach, with Ni as a catalyst and octachlorotrisilane (Si(3)Cl(8), OCTS) as a precursor, we achieved epitaxial growth of rectangular-shaped Si-NWs, which may have important implications for electronic mobility and light scattering in NW devices. The process parameters were adjusted to form cubic α-NiSi(2) particles which further act as the shaping element leading to prismatic Si-NWs.

Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor.

Perchlorinated polysilanes were synthesized by polymerization of tetrachlorosilane under cold plasma conditions with hydrogen as a reducing agent. Subsequent selective cleavage of the resulting polymer yielded oligochlorosilanes Si(n)Cl(2) (n) (+2) (n = 2, 3) from which the octachlorotrisilane (n = 3, Cl(8)Si(3), OCTS) was used as a novel precursor for the synthesis of single-crystalline Si nanowires (NW) by the well-established vapor-liquid-solid (VLS) mechanism. By adding doping agents, specifically BBr(3) and PCl(3), we achieved highly p- and n-type doped Si-NWs by means of atmospheric-pressure chemical vapor deposition (APCVD).

Subeutectic synthesis of epitaxial Si-NWs with diverse catalysts using a novel Si precursor.

The applicability of a novel silicon precursor with respect to reasonable nanowire (NW) growth rates, feasibility of epitaxial NW growth and versatility with respect to diverse catalysts was investigated. Epitaxial growth of Si-NWs was achieved using octochlorotrisilane (OCTS) as Si precursor and Au as catalyst. In contrast to the synthesis approach with SiCl(4) as precursor, OCTS provides Si without the addition of H(2).

Transhepatic dilatation of choledochoenterostomy strictures.

During the last seven years percutaneous transhepatic biliary drainage (THD) was used in 13 patients to relieve obstructive jaundice caused by postsurgical stricture. Nine patients had internal drainage with dilatation, and external drainage alone was feasible or available in 4 patients. Of these 4, 2 had further reconstructive surgery without lasting results, jaundice was not completely relieved in 1 because of biliary cirrhosis, and 1 died in hepatic coma from sclerosing cholangitis.

Intraoperative localization of intestinal arteriovenous malformation.

Intestinal arteriovenous malformation (AVM) is an uncommon cause of gastrointestinal hemorrhage and is difficult to diagnose. Selective visceral angiography is essential to make the diagnosis and to localize the lesion. We treated two patients in whom AVMs of the small intestine were located by means of arteriography and intraoperative selective mesenteric venous pressure and PO2 measurements.